Harvard geneticist Joseph Pickrell is part of a new generation of scientists talking about their data not just over the lab bench, but in conversations online. Pickrell uses the Internet to open himself, his research and his thoughts about others’ work to public scrutiny.

Pickrell (pictured) analyzes genetic data from people living today to reconstruct ancient evolutionary relationships. But he wouldn’t expect his research subjects to make their genetic secrets public if he wasn’t willing t...